The RAC Foundation has said new research suggests that scrapping the oldest cars registered in urban areas would have a negligible effect on air quality.

The RAC Foundation said it shows that vehicles responsible for emitting the most air pollution tend to be licensed at locations outside the most populous, relatively deprived urban areas, which are hardest hit by harmful emissions.

This applies on both a per kilometre and basis and annual basis, although the research highlights that the amount vehicles are used can be more important in determining their annual emissions than their per-kilometre emissions.

The most polluted areas tend to contain ‘older but cleaner cars’, the RAC Foundation said. Where older vehicles are registered in towns and cities they are likely to be driven less far and therefore produce, overall, relatively small amounts of nitrogen oxides, particulate matter and carbon dioxide.

Steve Gooding, director of the RAC Foundation, said: ‘The message is unmistakable. Targeting a scrappage scheme at the owners of old diesel cars in the most polluted areas is not going to get us where we need to be.

‘Scrappage might sound like a sensible quick fix, but the sad fact is that there is no easy solution to our air quality problems.

‘This report confirms that those on the lowest incomes are likely to have the oldest cars but reveals that more often than not they will be petrol rather than diesel. This probably reflects the fact that diesels only make up about a third of the total UK vehicle fleet and many of them will have been bought relatively recently by people thinking they were doing the environmentally-friendly thing.’

One of the report authors, Dr Tim Chatterton from the University of the West of England, Bristol, said: ‘It is time that UK air pollution policy stopped focussing solely on per-kilometre emissions from the vehicle fleet, and began to consider serious options for enabling less traffic on our urban roads.’

London’s £10 Toxicity Charge (T-Charge), said to be the world’s toughest emission standard, came into force on Monday morning as part of mayor Sadiq Khan’s plans to tackle air pollution.

Drivers of vehicles that do not meet the Euro 4 standards for both particulate matter (PM) and Nitrogen Oxide (NOx) emissions will pay both the T-Charge and the existing £11.50 Congestion Charge – a total of £21.50 – every weekday they drive in the Congestion Zone from 7am-6pm.

Transport for London (TfL) said up to 34,000 polluting vehicles every month could be liable for the T-Charge but that the number of older, more polluting vehicles driving into the zone is expected to fall. Its monitoring data reveals a drop of about 15% since Mr Khan announced the charge in February.

London mayor Sadiq Khan

Mr Khan said: ‘As mayor I am determined to take urgent action to help clean up London’s lethal air. The shameful scale of the public health crisis London faces, with thousands of premature deaths caused by air pollution, must be addressed.

‘Today marks a major milestone in this journey with the introduction of the T-Charge to encourage motorists to ditch polluting, harmful vehicles.’

AA president Edmund King warned that there was ‘no silver bullet’ to tackling air pollution and that the new charge ‘should not be seen as an excuse for the London boroughs to introduce their own charging or parking schemes which aim to demonise diesels’.

He said: ‘In the pursuit of cleaner air Londoners will need to be convinced that public transport is affordable and reliable enough to use. Failing that they will need assistance to convert non-compliant vehicles to ones which the mayor deems suitable.’

RAC roads policy spokesman Nick Lyes warned that those drivers likely to be most affected are those from lower income backgrounds as well as smaller businesses’.

Leonie Cooper, chair of the London Assembly Environment Committee, said: ‘We absolutely must do more to prevent premature deaths and stunting children’s lungs from air pollution – so we welcome the mayor’s T-Charge as a first step towards making London’s air less toxic.

‘However, the London Assembly Environment Committee believes even greater results could be achieved if the measures were implemented at a faster pace.’

Pre-Euro 4 vehicles are typically those registered before 2006. TfL advised anyone who has a car registered before 2008 to use TfL’s free online vehicle checker.

The Government has delayed its decision on the Silvertown Tunnel project’s planning application amid concerns over its impact on air pollution.

In a written parliamentary statement, transport minister Paul Maynard said ministers were extending by a further month the deadline for a decision, which was due today (11 October).

He told MPs: ‘This extension is to enable further consideration of the recent responses to the secretary of state consultations on the scheme which relate to the updated UK plan for tackling roadside nitrogen dioxide concentrations published by government on 26 July 2017.

‘The decision to set a new deadline is without prejudice to the decision on whether to give development consent.’

Campaign group Friends of the Earth (FoE) has argued that Transport for London (TfL) is wrongly relying on a finding that building the tunnel will not have a negative impact on the ability of London as a whole to comply with the European air quality directive, while admitting that it could worsen air pollution in some areas.

TfL said in response that while it is required to apply the test concerning London as a whole, it also believes the tunnel will have a positive impact on air quality in more local areas than would suffer a deterioration as a result of the project.

The dispute has echoes of the arguments over the air quality impacts of expanding Heathrow airport, which both parties oppose and which has also been affected by the Government’s changes to its national plan to bring nitrogen dioxide pollution within EU limits.

Prior to the announcement regarding the delay, a TfL spokesperson told Highways: ‘The scheme has been subject to extensive air quality assessment that shows it complies with the requirements set out in the National Policy Statement and results in an overall improvement in air quality.’

FoE air pollution campaigner Jenny Bates said: ‘This delay hopefully shows that the air pollution effects of this outdated four-lane road scheme are being taken seriously. This Silvertown tunnel would make already poor air quality even worse in some areas – and that is simply not acceptable.

‘Major road-building should have no place in a city which desperately needs to cut traffic levels and cut pollution. If Sadiq Khan is serious about protecting Londoners’ lungs he should pull the plug on this scheme, and look at cleaner alternatives.’

Caroline Russell, Green Party Member of the London Assembly, said: ‘The mayor’s toxic tunnel would blow the UK’s cleaner air plans out of the water in east London, people there already suffer from living in one of the most polluted parts of London.

‘I have been urging Sadiq Khan to bin the plans for this backwards-looking project and instead invest in cycling, walking and public transport river crossings. He has a great vision for healthy streets, but this scheme is totally at odds with that vision.

‘The mayor has consistently portrayed his stance on air pollution as more ambitious than the Government’s position but the boot is on the other foot this time. Delaying the decision on the Silvertown Tunnel shows just how worried the Government is about this scheme. It is clearly incompatible with the Government’s legal obligation to reduce nitrogen dioxide (N02) levels to safe limits in the shortest time possible.’